6-Aryl-4H-s-triazolo[3,4-c]-thieno[2,3-e]-1,4-diazepines, particularly brotizolam (R1=Br, R2=methyl, R3=Cl), are known for example from U.S. Pat. No. 4,094,984 and are valuable medicaments which have sedative properties, in particular, and may be used for treating sleep disorders.
However, the preparation described therein, starting from a 5-aryl-1,3-dihydrothieno[2,3-e]-1,4-diazepin-2-one of formula II, is unsuitable for production on an industrial scale, as the intermediate products involved, such as for example 5-aryl-1,3-dihydrothieno[2,3-e]-1,4-diazepin-2-thiones, have to be isolated, and when reacted give off foul-smelling and in some cases toxic thiols which may lead to contamination of the products.
The aim of the present invention is therefore to provide a process which makes it possible to synthesise, work up, purify and isolate 6-aryl-4H-s-triazolo[3,4-c]-thieno[2,3-e]-1,4-diazepines of formula I on an industrial scale while overcoming the disadvantages mentioned above.